Hydraulic unloader.



A. S. ANDERSON.

HYDRAULIC UNLOADER.

APPLICATION FILED JUNE 30. 19:5.

Patented Dec. 31, 1918.

2 SHEETS-SHEET 1.

A. S. ANDERSON,- HYDRAULIC UNLOADER.

APPLICATION man JUNE 30. 19:5.

1,289,599 Patented Dec. 31,1918.

2 SHEETS-SHEET 2.

' T 'm I ALBERT S. ANDERSON, OF ST. PAUL, MINNESOTA, ASSIGNOR TO GRANT WALDREF, OF

ST. PAUL, MINNESOTA.

HYDRAULIC UNLOADER.

menses.

Specification of Letters Patent.

Application filed .Tune 30, 1915. Serial No. 37,194.

ful Improvement in Hydraulic Unloaders,

of which the followingis a specification.

My invention relates to improvements in hydraulic unloaders for vehicles, the primary object being to provide a simple, light, compact, durable and easily operated apparatus for tilting the body of a vehicle for the purpose of quickly dumping the contents thereof.

- More particularly this invention relates to that class of hydraulic unloaders,wherein an impelling medium is circulated through a system of ducts for operating a piston which is associated with, the tilting body for raising and lowering said body. The subject matter of this application is an improvement upon the hydraulic dump, set forth in the application filed by Garfield A. Wood, on the 21st day of October, 1912, Serial Number 726,929, and is directed more particularly to means whereby lateral thrust upon the operating parts of the device is compensated, so that the working parts move freely without any binding efiort or unnecessary friction. This application does not claim broadly .the particular system of ducts employed for propelling the piston such structure being claimed in companion application executedthis day by Grant VValdref to whom my application has been assigned.

In the accompanying drawings forming part of this specification, Figure 1 is a side elevation partly in section of my invention showing part of anautomobile chassis. and a portion of a tiltable body thereon; Fig. 2 is a side elevation partly in section of a detail of my improvement; Fig. 3 is a front elevation of a detail; Fig. 4 is a section on the line X-X of Fig. 1 with controlling handles and part of structure broken away; Fig. 5 is a section on the line Y -Y, F1g. 1; Figs. 6 and 7 are sections of detalls pertaining to valve mechanism by which the pump is controlled in operation, and Fig. 8 is a perspective of a detail illustrating the manner in which the lifting cables are attached to the tiltable body of the vehicle.

in the drawings A indicates a portion of a chassis of an automobile truck and B a detail of the vehicle body which is tiltingly mounted upon the chassis in the customary manner, said body being provided with a pair of depending lifting. arms, which are spaced apart on the front end of the body as illustrated in Fig. 8. Mounted upon the chassis and secured thereto such as by bolts 2 and angle members 3 is a base 4 resembling a plate into which is threaded or otherwise fastenedthe upwardly extending hydraulic pylinder 5, the lower end of said cylinder be.

Patented Dec. 31, 1918..

mg connected with a passage Sextending forwardly and upwardly through the base. In the cylinder is a piston 7 having a hollow piston rod 8 extending upwardly through the packing flange 9, (see Fig. 4) in the upper end of the cylinder. The lower end of said rod is formed with passages 10 (see Fig. 1) entering the cylinder and rod, and the upper end of said rod carries a yoke 11 fitted closely thereto and provided-with a I passage 12 entering the piston rod, said pas sage containing an open threaded stopper 13. By removing the stopper 13, the cylinder can be filled with propelling fluid through the piston rod. The yoke 11 carries on each of its arms which are spread laterally from the piston rod a pair of links 14. These links are freely hung from the yoke and carry sheaves 15 positioned on opposite sides of the cylinder and over which travel a pair of flexible lifting cables 16. The forward lower ends of these lifting cables are secured pivotally to an equalizer arm 17 pivoted midway between its ends by a link 18 to a .coupler19, said coupler being in the form of a rod bent midway between its ends and having its ends'secured per manently to the base 4. The equalizer compensates for any uneven side thrust against the piston rod due to uneven loading of the body, uneven length of the lifting cablesor slanting of the vehicle laterally. The rearward lower ends of the lifting cables are attached to the lifting arms 1. When the piston moves upwardly in the cylinder, the sheaves force the cables '16 upwardly between their ends, thus lifting the load by a short upward stroke of the piston All of the parts as described are symmetrically arranged so as to assist in compensating uneven lateral strains and causing the piston and its rod to work evenly and smoothly with little or no binding efi'ort or tendency; Mounted upon the base 4 and secured by bolts 20 is a gear pump C having a pair of intermeshing toothed pump gears 25 and 26 carried by shafts 27 and 28, which 2111110111- ing is also formed with another passage 33 which leads from a port 30 upwardly through the top of the casing. Mounted upon the casing is a valve D which is seated in a valve housing 34. This valve housing is formed with a pair of passages 35 and 36 respectively connecting with the passages 32 and 33, in the pump casing and entering the valve seat in opposite position so as to be opened and closed independently by the valve. The valve housing also has another passage 37 entering the valve seat with which a pipe 38 is connected by the coupling 39, said pipe being also connected with the upper end of the cylinder above the piston, the point of connection between the pipe 38 and the cylinder being a short distance below the upper extremity of the cylinder. Thus the valve seat has three separate ports leading respectively and ultimately to the upper and lower ends of the cylinder and to the ingress opening of the pump c'ham ber. The valve D is of rotary conical type mounted in the valve housing on the valve seat, and is provided with a stem 40 by which the valve can be rotated. This valve is pressed firmly upon its seat to form a tight ,connection by means of a compression the valve D is controlled by a handle in the spring 41 bearing against its ends opposite The valve is formed with a transverse passage 42. When the valve is said stem.

moved into one position as illustrated in Fig. 6 the fluid 1 s conducted and forced by the gear pump 1nto the lower end of the cylinder, thus raising the piston and the load carried thereby.

v When the valve is moved into the position illustrated in Fig. 7 a short continuous circuit is formed for the fluid around the pump through the passages 33,32, 35 and 36 without forcing the piston upwardly. When the valve is moved into the position illustrated in Fig. 5 and the pump stopped, the fluid instead of passing through the pumpflows freely through the valve and the passage 32 independent of the pump, thus allowing the piston todescend and return slowly into normal position, partly by the weight of the body B,

and partly by gravity. The operation of form of a lever '45 pivoted upon a supporting member 46, which is secured to the cylinelement 51,

meeoee der 5. The free end of this lever handle has pivotally secured thereto a pitman 47, which in turn is pivoted to the free end of an arm 48 carried by the stem 40 of the valve, thus by raising and lowering the operating lever 45 the valve D is turned in its seat.

gagement with the driving element 50,

power is transmitted to the gear pump and the gears 25 and 26 of the pump revolved.

The driving element of the clutch carries.

a toothed shifting element 68 slidable diametrically across the axis of the propeller shaft with the teeth ofwhich the teeth 69. on the driven element 51 are engaged when the clutch is closed, said shifting element forming a universal coupling in the clutch and compensating any uneven motion of the clutch elements and propeller shaft. The actuating means for throwing the clutch into and out of operation consists of a handle lever 55 pivoted upon the sup-' port 46 and connected by a pitman 57- to one arm 58 of a bell crank lever. This bell crank lever is pivoted at its angle upon a supporting bracket 59. which is attached to a depending support 60, in which the gear member 52 is journaled. The other arm of the bell crank lever is freely connected by bifurcation 61 working in the channel 62 of a collar 63 journaled upon the sleeve 64 forming part of the-driven element 51 of the clutch. so that when the bell crank lever is tilted the driven member is thrown into or out of connection with the, driving element and clutch. To hold the arm 55 of the clutch operating mechanism in adjusted position with the clutch members in or out of engagement, the arm 55 is made to spring into releasable engagement with the teeth 65 of a quadrant 66 formed on the support 46. The lever arm 55 is flexibly mounted then moved upwardly until the valve assumes the position indicated in Fig. 6, whereupon the impelling medium is forced upwardly into the cylinder and the piston raised until it moves above the passage in the wall of the cylinder to which the pipe 38 is, connected. While the piston is rising the chamber in the piston rod supplies propelling medium to the pump, said chamber being open to the outer atmosphere allowing the fluid to pass freely to the pump as required to fill the space in the cylinder below the piston. Upon reaching uppermost position the body remains tilted while the pump continuesin operation, the fluid thereupon passing continuously through the cylinder and back to the pump through the pipe 38. If the pump is then stopped the impelling medium below the piston holds the piston in superior position. To lower the body the pump is stopped and the valve is moved by swinging the handle until it assumes the position illustrated in Fig. '5, whereupon the propelling medium escapes the pump gears and is conducted by passage 32 upwardly, allowing the piston to descend freely and slowly according to the valve opening.

' While the piston is lowering the impelling medium displaced below the piston in the cylinder fills the space above the piston and in the piston rod. Thus the piston rod acts as a displacement chamber as well as performing its usual function and the use of a tank or other chamber independent of the cylinder is obviated.

By providing the mechanism disclosed for equalizing and compensating uneven lateral thrusts upon the parts and by arranging the parts symmetrically, even and smooth operation is imparted to the mechanism under the widely varying conditions required to which devices of this character are subiect.

As a result of my invention the construction is simple, compact, light, durable and easily operated.

In accordance with the patent statutes, I

have described the principles of operatlon of my invention, together with the'apparatus which I now consider to represent the best embodiment thereof, but 1 desire to have it understood that. the construction shown is only illustrative, and that the in vention can be carried out by other means and applied to uses other than those above set forth within the scope of the following claim. 7

Having described my invention, what I claim as new and desire to protect by Letters Patent is: p

A device of the type described, comprising, in combination, a vehicle having a tiltable body, a platform mounted upon the vehicle, a motor driven hydraulic cylinder mounted upon said platform and having a piston provided with an upwardly projecting'piston rod, a yoke on the upper end of said rod, links hung from said yoke on opposite sides of said rod, sheaves journaled in said links, a compensator near the lower forward portion of said cylinder, a rod bent between its extremities having its ends attached to said platform, a link freely attached to the medial portion of said rod and the medial portion of said compensator, and flexible connections traveling over said sheaves and connected to said compensator and said tiltable body.

In testimony whereof, I have signed my name to this s ecification.

KLBERT s. ANDERSON. 

